1. Field of the Invention
The present invention relates to an apparatus for coating a wafer with a photoresist in the manufacture of a semiconductor device, and more particularly, to an apparatus for coating a wafer with a photoresist that is to be etched in the manufacture of the semiconductor device.
2. Description of the Related Art
Generally, an apparatus for coating a wafer with a photoresist, as shown in FIG. 1, comprises an outer body 1 having an open top, and a spin chuck 2 loaded with a wafer W and disposed inside the outer body 1. The spin chuck 2, which is integrated with and driven by a driving part 3, penetrates the bottom of the outer body 1 and revolves to rotate the wafer W fixed thereon.
The outer body 1 has a bowl-like shape and its top is located above the spin chuck 2 to prevent photoresist from being spattered out of the outer body 1 during the photoresist coating operation. A photoresist dispensing nozzle 4 and a side rinse nozzle 5 are installed on the top of the outer body 1. These nozzles 4, 5 move up and down relative to the wafer.
An inner bowl 6 is installed within the outer body 1 to prevent photoresist from spattering on the outer body 1. The bowl 6 is made of a heat resistant, scratch resistant, non-stick material (e.g., TEFLON) so that any photoresist existing on the surface of the outer body 1 can be removed easily. The inner bowl 6 must be changed regularly for cleaning.
The wafer W placed on the spin chuck 2 of the outer body 1 is fixed thereto by a vacuum created by the spin chuck 2, and then the photoresist dispensing nozzle 4 and the side rinse nozzle 5 move downward to apply photoresist to the wafer. At the same time, the spin chuck 2 driven by the driving part 3 revolves at a constant rate and photoresist is sprayed on the wafer surface and spread uniformly thereover by centrifugal force.
The rinse solution supplied from the side rinse nozzle 5 removes any photoresist adhered to the peripheral edge of the wafer, and the rinse solution and the removed photoresist are drained through an outlet 7 of the inner bowl 6.
After the entire surface of the wafer is coated with photoresist, the photoresist dispensing nozzle 4 and the side rinse nozzle 5 move upwards, the spin chuck 2 stops revolving, and the wafer having the photoresist thereon is transferred to the next processing station.
However, the cleaning of the conventional apparatus requires changing the inner bowl 6. This takes much time and the inconvenience significantly affects the production rate of the facility.
Further, since the photoresist supplied from the photoresist dispensing nozzle 4 is exposed to the atmosphere during the coating process and the solvent element of the photoresist is volatilized, its viscosity is increased. Thus, the photoresist is not uniformly coated on the wafer. The uniformity of the photoresist layer is critical to prevent difficulties downstream in manufacturing a semiconductor device having precise dimensions.